For my 5e Iron Gods game. Characters swiftly dealt with this fella. They managed to sneak up and put a grenade in its mouth before it woke up. The rogue and monk who were doing the sneaking made a beeline away from the mutant before the grenades went off.
Large monstrosity, chaotic evil
Armour Class 15 (natural armour)
Hit Points 180 (12d10 + 60)
Speed 30’ ft.
Str 23 (+6) Dex 11 (+0) Con 21 (+5)
Int 3 (-4) Wis 14 (+2) Cha 10 (+0)
Skills Perception +8
Damage Resistances bludgeoning, piercing, and slashing from nonmagical weapons.
Senses Darkvision 60 ft., passive Perception 18
Challenge 7 (2,900 XP)
Brute. The yaoguai deals one extra die of its damage when it hits with a natural attack (included in the attack).
Keen Smell. The yaoguai has advantage on Wisdom (Perception) checks that rely on smell.
Polymorph Susceptibility. A yaoguai is immune to polymorph effects or affects that otherwise change its shape, but the attempt to alter its shape causes it great pain and it must attempt a saving throw if the effect allows it. If it fails its save or the effect doesn’t allow a saving throw, the yaoguai is stunned and loses its damage resistance and regeneration for 1d4 rounds.
Regeneration. The yaoguai regains 10 hit points at the start of its turn until reduced to 0 hit points.
Multiattack. The yaoguai makes three attacks: one with its bite, one with its tentacles, and one with its claws.
Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target.
Hit: 18 (3d8 + 6) piercing damage.
Claws. Melee Weapon Attack: +9 to hit, reach 5 ft., one target.
Hit: 14 (3d6 + 6) slashing damage.
Tentacles. Melee Weapon Attack: +9 to hit, reach 15 ft., one target.
Hit: 15 (3d6 + 6) bludgeoning damage. If the target is a creature, it is grappled (escape DC 16). Until this grapple ends, the target is restrained, and the yaoguai can’t use its tentacles on another target.
This creature is a mix of different animals fused together, with a bear’s torso and head, clawed ape legs, and a furred tentacle arm.